Fetcher now required with all transaction building (it shouldn't)

[twwu123]

Describe the bug
Currently, the APIs don't make it possible to input ref script into TxIn. This is troublesome, because it is required for fee calculations, making it impossible for offline transaction building.

Additional context
Simply need to change TxIn to have an extra field for ref script size.

[twwu123]

Further changes might be needed with regards to inputting the UTxO type into transaction builders.